The disclosure relates generally to high-silica content substrate materials, and specifically to high-silica content substrate materials for use in light emitting diode (LEDs) formation methods. Silica soot may be generated by a process, such as flame hydrolysis. The silica soot may then be sintered to form a fully or partially sintered high-silica content substrate. LEDs include a diode which generates light and a phosphor layer which absorbs at least some of the light from the LED and generates light at different wavelengths. The LED and phosphor layer are supported by a substrate.